Analysis of Induced Current of OPGW in 750 kV Transmission Lines

In recent years, the use of optical fiber composite overhead ground wires (OPGW), which are a combination of optical fibers and overhead ground wires, has become increasingly common due to the growing demand for reliable and secure communication links in power transmission and distribution systems. In high-voltage transmission lines, the all grounding method is commonly used for OPGW. Due to electromagnetic induction, there is an induced electromotive force on the ground wire, creating a loop between the towers and generating induced currents. These induced currents result in power losses. This study establishes a single-circuit model of a 750 kV transmission line using typical towers, with two OPGW cables employed and an all grounding configuration. The distribution of induced currents and ground currents along the line is investigated. Additionally, the effects of three operational parameters, namely, ground resistance, span distance, and conductor transposition, on induced currents are discussed. The results indicate that span and ground resistance have a relatively small impact on ground-induced currents, while ground resistance has a more significant influence on ground currents. On the other hand, conductor transposition has a substantial effect on both induced currents along the ground wire and currents into the earth.